The described aspects relate generally to wireless communication systems. More particularly, the described aspects relate to techniques for feedback signal management for low latency wireless communications.
Wireless communication systems are widely deployed to provide various telecommunication services such as telephony, video, data, messaging, and broadcasts. Typical wireless communication systems may employ multiple-access technologies capable of supporting communication with multiple users by sharing available system resources (e.g., bandwidth, transmit power). Examples of such multiple-access technologies include code division multiple access (CDMA) systems, time division multiple access (TDMA) systems, frequency division multiple access (FDMA) systems, orthogonal frequency division multiple access (OFDMA) systems, single-carrier frequency division multiple access (SC-FDMA) systems, and time division synchronous code division multiple access (TD-SCDMA) systems. These multiple access technologies have been adopted in various telecommunication standards to provide a common protocol that enables different wireless devices to communicate on a municipal, national, regional, and even global level.
An example of an emerging telecommunication standard is Long Term Evolution (LTE). LTE is a set of enhancements to the Universal Mobile Telecommunications System (UMTS) mobile standard promulgated by Third Generation Partnership Project (3GPP). It is designed to better support mobile broadband Internet access by improving spectral efficiency, lower costs, improve services, make use of new spectrum, and better integrate with other open standards using OFDMA on the downlink (DL), SC-FDMA on the uplink (UL), and multiple-input multiple-output (MIMO) antenna technology. However, as the demand for mobile broadband access continues to increase, there exists a need for further improvements in LTE technology. Preferably, these improvements should be applicable to other multi-access technologies and the telecommunication standards that employ these technologies.
In wireless communication systems employing LTE, a user equipment (UE) served by one or more eNodeBs can receive control channels, which provide resource grants for transmitting or receiving UE data, and one or more data bearer channels, which provide UE data. With development of lower latency communications, a shorter transmission time interval (TTI) (e.g., a TTI less than the 1 millisecond TTI of LTE) is supported. When a UE operates using lower latency communications with a network, the UE may asynchronously or simultaneously receive one or more grants from the network at different stages. In order to maintain proper low latency communication with an eNodeB, the UE may transmit an acknowledge (ACK) or a negative acknowledge (NACK) message to the eNodeB to indicate whether the one or more grants are successfully received.
Therefore, there is a desire for improvements in techniques for managing feedback signals to the network when the UE receives one or more grants from the network when operating with lower latency communications.